com.google.javascript.jscomp

Class ShadowVariables

java.lang.Object

com.google.javascript.jscomp.ShadowVariables

All Implemented Interfaces:

CompilerPass

class ShadowVariables
extends java.lang.Object
implements CompilerPass

Tries to compute a list of variables that can shadow a variable in the outer scope. For example: var a = function() { var b = getB(); b(); return function(y) {}; }; Normally, b would be mapped to variable L0, y would be L1. Instead we are going to make y shadows L0 in hope of using less variables and reusing frequently used local names.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	ShadowVariables.DoShadowVariables
private class	ShadowVariables.GatherReferenceInfo

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Map<java.lang.String,RenameVars.Assignment>	assignments
private AbstractCompiler	compiler
private java.util.Map<Node,java.lang.String>	deltaPseudoNameMap
private java.util.Map<Node,java.lang.String>	oldPseudoNameMap
private com.google.common.collect.Multimap<Node,java.lang.String>	scopeUpRefMap
private java.util.SortedSet<RenameVars.Assignment>	varsByFrequency
private com.google.common.collect.Multimap<Var,Node>	varToNameUsage

Constructor Summary

Constructors

Constructor and Description
ShadowVariables(AbstractCompiler compiler, java.util.Map<java.lang.String,RenameVars.Assignment> assignments, java.util.SortedSet<RenameVars.Assignment> varsByFrequency, java.util.Map<Node,java.lang.String> pseudoNameMap)

Method Summary

Modifier and Type	Method and Description
void	process(Node externs, Node root) Process the JS with root node root.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

scopeUpRefMap

private final com.google.common.collect.Multimap<Node,java.lang.String> scopeUpRefMap

varToNameUsage

private final com.google.common.collect.Multimap<Var,Node> varToNameUsage

compiler

private final AbstractCompiler compiler

varsByFrequency

private final java.util.SortedSet<RenameVars.Assignment> varsByFrequency

assignments

private final java.util.Map<java.lang.String,RenameVars.Assignment> assignments

oldPseudoNameMap

private final java.util.Map<Node,java.lang.String> oldPseudoNameMap

deltaPseudoNameMap

private final java.util.Map<Node,java.lang.String> deltaPseudoNameMap

Constructor Detail

ShadowVariables

ShadowVariables(AbstractCompiler compiler,
                java.util.Map<java.lang.String,RenameVars.Assignment> assignments,
                java.util.SortedSet<RenameVars.Assignment> varsByFrequency,
                java.util.Map<Node,java.lang.String> pseudoNameMap)

Parameters:

assignments - Map of old variable names to its assignment Objects.

varsByFrequency - Sorted variable assignments by Frequency.

pseudoNameMap - The current pseudo name map so this pass can update it accordingly.

Method Detail

process

public void process(Node externs,
                    Node root)

Description copied from interface: CompilerPass

Process the JS with root node root. Can modify the contents of each Node tree

Specified by:

process in interface CompilerPass

Parameters:

externs - Top of external JS tree

root - Top of JS tree